Here’s a lovely take from Osho on what it means to be sinful and sinless:
Anything that stops your evolution in consciousness is evil. It is a sin.
And anything that helps you to move toward more consciousness is a virtue.
That's the only definition that I can give to you.
Be more aesthetic, be more sensitive, be more respectful of life, because you are part of it.
Whoever you are killing, you are killing yourself. Your destructiveness is suicidal.